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Now, let's talk about fat emboli.

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Fat emboli is usually associated with long

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bone fractures or with patients who have

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sickle cell disease or sickle cell trait.

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What happens is marrow gets released

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into the bloodstream and the fat emboli

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pass into the cerebral capillaries and

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cause a starry sky appearance with too

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numerous to count little foci of restricted

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diffusion throughout gray and white matter.

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As you can see, in the region of

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the supratentorial brain, superiorly

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frontal and parietal lobes, more

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inferiorly involving the basal ganglia.

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The deep white matter including the corpus

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callosum, some lesions extending out to cortex.

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Usually it takes one to two

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days for the symptoms to appear.

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And what happens is the fat emboli eat through

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the capillaries, so you'll get too numerous

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to count little microhemorrhages throughout

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the brain in association with the fat emboli.

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This is a case of fat emboli.

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These are images of a 27-year-old

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female who had a tibial fracture.

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And then two days later.

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Started having mental status changes and

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difficulty speaking, and you see the diffusion

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weighted images, the ADC images, you can see

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multiple acute infarcts are bright on DWI,

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dark on ADC, you can see them throughout

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the cerebellum, too numerous to count, and

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throughout the supratentorial brain, temporal

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and occipital lobes here, and you can see

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they also involve the deep white matter,

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and the thalami, and the caudate, And the

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periventricular white matter and the subcortical

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white matter and some are out in cortex.

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And this is very classic of a shower of emboli.

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We'll show you the FLAIR images as well.

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So you can see the lesions on FLAIR

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images too, so they're subacute infarcts.

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And what we're going to do is now look

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at the susceptibility weighted images.

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And when I look at the susceptibility

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weighted images, you can see multiple foci

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of susceptibility and we're going to keep

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going up and you can see all these foci

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of susceptibility in the white matter,

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especially in the corpus callosum here.

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in the subcortical white matter.

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Again, just too numerous to count

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multiple foci of susceptibility.

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And when we put them next to the diffusion

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weighted images, you can see that these foci

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of susceptibility are in regions where you've

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got, um, diffusion abnormalities as well.

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And so this is a classic fat emboli

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syndrome, long bone fracture,

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several days later, symptomatic.

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A starry sky appearance, too numerous to

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count lesions everywhere, deep gray nuclei,

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supratentorial and infratentorial brain,

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white matter cortex, and then numerous foci

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of susceptibility because remember the lipases

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eat through the vessels and cause hemorrhage.

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So this case is characteristic of fat

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emboli, but it's important to make

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sure that you're not missing something

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and that the vessels are normal.

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So we did a contrast-enhanced MRA of the

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neck and you can see the right subclavian

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and the right common and internal and

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external carotid arteries are normal.

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The right vertebral artery also looks

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normal as we scroll through the images.

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And then we'll take a look at the left

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side and the left side, the left common

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internal and external look normal as we.

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scroll around, we can see the vertebral

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artery also looks completely normal.

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And then we'll just look

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at the circle of Willis.

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We did a 3D time-of-flight of the circle

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of Willis and you can see the right

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internal cerebral artery and the left

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internal cerebral artery look normal

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and the right MCA looks normal and

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the left MCA and the ACAs look normal.

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We can just tumble it in

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the other direction as well.

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Um, so again, middle cerebral

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arteries, anterior arteries.

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posterior cerebral arteries,

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vertebral arteries all look normal.

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So this helps us confirm our

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diagnosis of fat emboli syndrome.